Application of silver-based contact materials in air-break switching devices for power engineering

The properties of some commonly used silver-based contact materials are discussed on the basis of the various metallurgical processes occurring in the interaction of the electric arc with the contact material. Using selected examples taken from research work and field experience, it is pointed out how the contact properties are influenced by the metallurgical mechanisms involved. Good results are obtained by using contact materials like Ag/MeO (with MeO standing for metal oxides such as CdO, ZnO, or SnO/sub 2/), Ag/Ni, Ag/C, Ag/W, and Ag/WC. Each of these materials has its own typical profile of properties, which are briefly reviewed, and which define the field of application and the type of switching design where it gives best performance.<>